Reversible two-way tumble plow



March 17, 1953 R. A. WALKER ET AL 2,631,512

REVERSIBLE TWO-WAY TUMBLE 1.0w

Filed March 9, 1951 3 Sheets-Sheet l M/VI/Vrm: Rial-R771- WALKER EARL V- WALKEQ ltlorney March 17, 1953 R. A. WALKER ET AL REVERSIBLE TWO-WAY TUMBLE, PLOW 5 Sheets-Sheet 2 Filed March 9, 1951 Invenlors .RUBERTA- WALKER 9'-' Attorney March 17, 1953 WALKER ET AL 2,631,512

REVERSIBLE TWO-WAY TUMBLE PLOW Filed March 9, 1951 3 Sheets-Sheet 5 I I E] aw M I 1908597' 4. WALKER g {3 3 54/?4 v WALKER Attprney Patented Mar. 17, 1953 UNITED STAT ES ATENT OFFICE Rob rt Walk a l alke Lin l Wy Application March 9, 1951, Serial No. 214,718

'7 Cla m 1 This invention relates to an improved constructlon of two-way reversible tumble plow and more particularly to an automatic means for controlling the reversing of the plow whereby manual operations are eliminated together with the possibility of incorrect manual operation.

More particularly, it is an aim of the present invention to provide an improved construction of plow embodying novel automatic features for use with a tumble plow of the type as shown in-U. .8. Patent 1,915,866 wherein a possibility of the plow being inadvertently unlatched to tumble when the. frame is unlatched and lowered from an elevated, transport position is eliminated.

Another object of the invention is to provide an improved .means to automatically adjust the center line of the draft which is accomplished without any manual operation automatically as the tumbling of the plowbeam iscomplete'd which in addition to eliminating a manual operation also enables the plow to be turned more slowly and less sharply at the end of afield.

A further object of the invention is to provide automatic means to positively prevent the latching of a wheel in a .fullylowered position as sometimes occurs with a manually actuated latch new employed with tumble plows when the furrow engaging wheel :is released before the 210w has reached a furrowinto which the wheel is to drop and whichis necessary .in order that plows may assume 'a sub-soil, furrow forming liosition at the end of the field.

Various other objects "and advantages of the in ntion Will ereinafter become more .fully apparent from the following description f drawings, illustrating a presently preferred embodiment thereof, and wherein:

re 1 is a s e el vational yiewshowing a plow emb dying he inv t on in a workin position and disposed for throwing the earth to the left or toward the farside of the plow;

Fi r i a p p View of the plow with certain of the parts omitted for clarity;

Figure 3 is an enlarged fragmentary side elevational view pa tly in vertical se t on showin the parts as illus ra ed in Fig re 1 prior to unlat h ng th ame rom a el vated. transp rt position for rmittin he frame to assume its pos tion of F ures 11 and '2;

i re is a enlarged longitudinal substantially e tral sectional view of a portion of the plow, on an enlarged scale and taken substantic-11y a ne a p a e as indicated by the n of Figure 2, and

Figu 5 a i aement ry perspective wiew of a portion of the plow illustrating the-improved construction of latch releasing means.

Referring more specifically to the drawings, as most of the structure of the plow, designated generally 9 and comprising the invention is identical or substantially identical with the plow as disclosed in Patent 1,915,866, reference is made to said patent for a detailed disclosure of such parts which will be. described herein only in reference to the extent that said parts are modified in their construction or operation by the improvements embodied in the present invention. Further, for the purpose of simplicity the parts as disclosed in the plow 9 will be referred to by reference numerals corresponding to the identical parts in Patent 1,915,866.

Said identical or substantially identical vparts include a draft bar 14 which is pivoted on a pin 15 intermediate of its ends and which pin connects the draft bar to the plow frame at its forward end. The frame is formed by the side bars to and H whichare suitably braced intermediate of their ends and which are provided with inwardly offset rear ends I9 and 20, respectively, which are connected by a transverse shaft 2|. A beam structure, designated generally 39 is journaled intermediate of its ends'on the shaft 2! for rotation about said shaft as a horizontal axis and includes correspondingcross members 34 and 35 defining the end portions of the beam structure. The beam structure so has a pair of right-hand plow bodies 36 and 52 projecting from one side of the plane thereof and a pair of left-hand plow bodies 38 and so projecting from the opposite side of the plane thereof, one of which pairs of plow bodies are disposed above the beam structure when the other pair of plow bodies are in an operative position, as illustrated in Figure 1.

The plow includes the two transversely aligned left and right ground wheels l9 and H journaled on the ends of axles l2 and i3, respectively, said axles having vertical portions slidably and turnably mounted in sleeves T5 of brackets '34 which are secured to the frame sides l9 and H. Each frame side is yieldably supported relatively to the adjacent axle by a contractile spring 16 which is secured at its lower end to the frame and at its upper end to a sleeve or collar H which is slidably and turnably mounted on the reduced upper end of the axle 12 or 13.

The wheels and axles are vertically adjusted relatively to the plow frame to, H by levers 89 each having a bifurcated rear end straddling its associated sleeve l5 and connected for vertical swinging movement by a pivot pin 32 to a bracket 83 which extends rearwardly from the sleeve I5. A lever member 34 is also pivoted to each pin 32 and extends forwardly of the sleeve and is pivotally connected at its forward end to a lateral end 85 of a link 86. Each link 86 extends upwardly and is pivoted at its upper end to the sleeve i1 disposed thereabove. Each lever 33 carries a latch 88 operating over a toothed sector 83 fixed to the sleeve I5. The levers 8% with their latches 88 released may be swung downwardly at their outer forward ends and in so moving will fulcrum on the link'portions 85 to swing the ends pivoted at 82 thereof upwardly for elevating the frame It, II relatively to the wheels I and II, aided by the spring l5.

The beam structure 30 is latched against rotation and in substantially a horizontal plane by a latch 90 which engages under one of the beam ends 34 or 35. The latch 93, as best illustrated in Figures 3 and 4 is pivoted at ill to a bracket 92 which is secured to a cross brace I3 extending between the frame parts It and Ii. Latch 96 has a forward projection 94 pivoted to one end of a link 95 by a pin 96. The other end of link 95 is pivoted on the laterally bent end all of a rod 98 which is likewise pivoted to the forward end of a U-shaped member 99, the rearwardly extending legs of which straddle the latch 99 and the lower end of bracket 32 and are pivoted to the latter by a pivot pin 5% which extends loosely through a slot I32 in the latch 99 whereby said latch can swing relatively to the member 93. One end of a spring I63 is connected to the rod end 91 and the other, rear end of said spring is connected to a pin I34 carried by the ears I95 of the bracket 92. A latch I95 is pivoted on pin I64 and is urged to a position to engage over either the beam end 34 or the beam end 35 by a spring IBM. The laterally bent upper end IEI'I of the trip rod 38 operates in the slot I98 which extends longitudinally of a trip lever I09. Whereas in Patent 1,915,866, said slot I38 must be of a predetermined length, the slot I38 of the present invention may be of any desired length as said slot is not intended to limit the movement of the end It! when the lever I33 is swung forwardly, as will hereinafter become apparent. A rope or cable I I e is connected to the upper end of the lever I33 and ex-- tends forward to a position where it can be grasped by the operator of a tractor ll to which the plow is coupled. The lever IE9 is normally retained in its rear full line position of Figures 3 and 4 by the spring I33. When thus disposed, the beam structure 30 is latched against rotation relatively to the frame I0, II.

Each bracket 14 is provided with arr extension I23 on which is pivoted a latch lever I2I, near but spaced from the rear end of said latch lever. A spring I22 urges each latch I2I to swing clock wise and such movement is limited by the forward end of each latch engaging a crank I23 on the end of a crank shaftl24, said shaft having a crank at each end thereof and having the trip lever $69 fixed to an intermediate portion of said shaft.

A latch I38 is pivoted on each bracket extension I 23, said latches I30 being urged to swing counterclockwise as seen in Figures 3 and 4 by the springs I22 and being limited in counterclockwise swinging movement by engagement with the toothed sectors 89. Each latch I33 has a hook I 3! facing downwardly and rearwardly adapted to engage a link end 85. The latches E30 are alternately disabled from engaging a 1 2 end 35 by a tripping ring I32 which engages the crank end 533 which is formed integral with the latch I 36 and disposed below the pivot thereof. Each beam end 34 and 35 carries a tripping ring I32, which tripping rings are disposed adjacent the opposite ends of said beam ends so that the latches I38 are thus alternately disabled.

The parts previously described are disclosed in Patent 1,915,866 and the operation of these parts has therefore not been described in d tail. Further, other less essential parts of the present invention corresponding to those of the prior patent have not been described. However, certain of the parts previously described are modified to a certain extent for accomplishing the novel automatic results of the present invention to render the plow automatic in operation and substantially foolproof. In furtherance of this end, the side frame members It and II near their forward ends are provided with transversely aligned bearing hangers I'Iil in which a transverse shaft I'lI is journaled. A lever I12 is fixed to the shaft IIi adjacent each end thereof. The levers I12 extend rearwardly from the shaft Ill and are each provided with a longitudinally elongated slot I13 adjacent its rear, free end. Each of the latch levers Iili is provided with a forwardly projecting extension Il i having a downturned forward free end to which one end of a link I is pivotally connected by a pivot pin I75. The two links I75 extend downwardly from the latch extensions I'M and are slidably and pivotally connected at their lower, free ends each by a pivot pin Ia'l to the rear end of the lever II2, disposed therebeneath. The pivot pins I'I'I slidably and turnably engage in the slots I13. A contractile coiled spring H3 is secured at its lower end at I13 to each latch lever I2 I, forwardly of the latch lever pivots and said springs I I8 extend upwardly and rearwardly and are secured at their'opposite ends at I33, each to the link 86 which is disposed substantially in alignment therewith. The springs We are connected to the links '85 adjacent the upper ends of said links but could be equally well connected to the sleeves I7.

Referring to Figures 3 and 5, an arm I8I is journaled on the crank shaft I24 on one side of the trip lever I09 and projects upwardly therefrom and rearwardly'with respect to said trip lever and has a laterally projecting free end I82 which extends in a direction away from the trip lever I99. The arm I 8| is provided intermediate of its ends with a laterally projecting pin I33 which extends in the same direction as its end I82 and which loosely engages an elongated longitudinally disposed slot I84 in one end of a connecting rod or link I85. The link I85 extends downwardly and forwardly from the pin I83 and is pivotally connected at I86 at its lower, forward end to the free end of a lever I8'I. The lever I8! is fixed to and projects rearwardly from the shaft I'II, intermediate of theends of the latter. A contractile spririgIBS is anchored at one end to the extension I82 and extends downwardly and forwardly therefrom and is anchored at its opposite endto'the connecting rod I85, forwardly of its slot' I84 and functions to support the arm I8I in its position to Figures 3 and 5. The spring I88 additionally functions to retain the slotted rod portion I84 in engagement with the pin I83. 1

One leg of a substantially U-shaped bracket IE3 is secured to the rear edge of the trip lever I03 "for'supporting the'bracket behind and in lat rally offset relationsh p o the trip lev r- An elongated slot closing slug I90 is pivotally connected near its upper end by a pin I9I to the bracket I89 and is supported by said bracket in laterally offset relationship to the trip lever I09 to swing across one side thereof. A guide I92 is fixed to and projects from the back edge of the trip lever I09, below the bracket I09 and has a hook portion at its rear end engaging around the back edge of the lower portion of the slug I90. Said member I92 functions with the bracket I89 for guiding the swinging movement of the slug I90 in a plane substantially parallel to the plane of the lever i99 and laterally onset relationship thereto. The guide i9?! additionally i'unctions as a stop for limiting the swinging movement of the slug I90 rearwardly of the lever I09 in a clockwise direction on its pivot 595. A spring 93 is anchored at one end to the lever I09 and is connected at its opposite end to the upper terminal of the slug I99, above its pivot I 9I to urge said slug to swing in a clockwise direction for displacing the lower portion of the slug away from and rearwardly with respect to the slot I09. The slug I90 is provided with an extension arm I94 which extends downwardly from its bottom edge and adjacent its back edge and which has a laterally projecting free end portion I95 which extends across the arm IBI and is disposed in front of said arm, as clearly illustrated in Figures 3 and 5.

Referring to the operation of the plow as described in Patent 1,915,866, after the plow beam has been tumbled in order to release the latch members I 2 I from engagement with the link ends 85 to allow the members 85 to swing upwardly to engage either one of the hooks I 3i or the lever 80, the trip lever I09 is swung forwardly slightly by a pull on the rope I I0 to swing the cranks I23 upwardly to rock the latches I2I counterclockwise to their released, dotted line positions of applicants Figure 3. The slot I130 of the patented structure permits this operation to occur without a downward thrust being exerted on the link 98. However, it will be readily apparent that should the rope IId be pulled too forcibly its latch 90 would also be released to allow the plow beam to tumble. However, with applicants structure the slot 4-93 may be made r sumc'iently long so that regardless of how far the trip lever I99 is swung forwardly th links 99 will not be displaced downwardly and consequently the latch 90 cannot be released, so long as the slug I90 is in its retracted position of Figures 3 and 5, which position it will always assume when the plow is in .a transport position, as illustrated in Figure 3, for a reason which will hereinafter be described. Accordingly, after the beam. structure has been released and turn- 'oled a forward pull is exerted on the rope lie to swing the trip lever I09 forwardly to elevate the cranks I23 therebyrocking the latch levers I2I counterclockwise to disengage them from the link ends '35 to allow'the members 8 5 to swing upwardly. The members 54 will 'be engaged, one by one of the latch hooks I310 and the other by one of the levers 80, after being released by the. latch levers IZI, in the same manner that said members 94 and link ends are caughtin the operation of the plow of Patent 1,915,856. However, when this occurs the frame I0, II will move downwardly relatively to the wheels and axles and with respect to the sleeve I1 and links 85 and the springs I'I8 which have been slacked while the frame is in its ra sedmsition o i ure. .3. are thereby tensioned by a downward movement of the frame so that said spring exert an upward pull on the latch levers I2I forwardly of their pivots and thus function to retain the latch levers in their inoperative positions as seen in dotted lines in Figure 13 and in full lines in Figure 4, in which positions the rear ends of the latch levers I2I are incapable of engaging and latching the link ends in their positions of Figure 3. This is of particular importance since ordinarily the transport latches I2I are rocked to their released positions before the plow reaches the end of a furrow into which one of the wheels is dropped, after making a turn at the end of a field, in order that the plow elements may assume sub-soil positions at the end of the field. Consequently, the wheel which is in a lowermost position relatively to the frame and which is to travel in the furrow will drop into the furrow. When this occurs or when the wheel strikes a hole in the furrow the wheel will drop downwardly relatively to the frame, assisted by the spring I6 connected to the axle of said wheel and if care is not exercised the associated member 84 and the link end 85 will swing downwardly and be relatched by the transport latch I iii in the position of Figure 3 and while the other wheel is in a fully raised position so that the plow element nearest the wheel will be completely out of the ground'and neither plow element will operate at the desired depth. In the plow of the prior patent the transport latches it! immediately return .to positions to relatch the link ends 85 after being rocked by the cranks I23 to released positions. However, with the present structure the tension on the springs I18 maintain the transport latches I2I in their released positions of Figure 4 and thereby effectively prevent this inadvertent relatching of one side of the frame in a transport position.

Likewise, the springs 51% in rocking the transport levers 52f to their positions of Figure 4 exert an upward pull on the links I15 either of which is capable of swinging its associated lever I12 upwardly to turn the shaft I'Ii clockwise from its position of Figure 3 to its position of Figure 4. t hen. this occurs. the lever arm i3] is swung upwardly and forwardly to its position of Figure 4 and in so moving exerts a forward pull on the connecting rod 585 to move it from its position of Figures 3 and 5 to its position of Figure 4. When this occurs, after the connecting rod is moved relatively to the arm Idl as provided for by the slot led, the rear end of said slot will engage the pin I93 to swing the arm i8! in a clockwise direction relatively to the shaft 526 on which it is journaled from its position of Figures 3 and 5 to its position of Figure 4. In so moving. the arm 15% will strike the extension I95 to dis place it forwardly and thereby swing the slug I80 counterclockwise on its pivot 5,95 from its posit-ion Figures 3 and 5 to its position of Figure l. In this latter position, the bottom edge of the slug till! extends across one side of the slot I08 above the link end 40?, which is disposed in the lower end of said slot and thus provides a slot closure to prevent the link end Iii": from sliding upwardly relatively to the slot its. It will thus be readily apparent that when the plow 9 has reached the end of the field the latch 99 can be readily released by a pull on the rope i It]. When this occurs'ahd assoon as the. trip lever I99 starts to swing forwardly a downward thrust is y exerted on the link 98 ior swinging t parts .95

and 93 downwardly so that the link 95 exerts a pull on the latch 90 to swing the latch forwardly to a disengaged position for releasing the beam 30 so that the tumbling thereof can be accomplished, as described in the patented plow structure.

A in the patented plow structure, means is provided in the plow 9 to effect automatic adjustment of the draft line from one side of the center line of the draft vehicle to the other side thereof so that one wheel of the draft vehicle will run in the furrow or foruse with plow bodies plowing furrows of different widths. However, with the present plow this shifting of the draft connection each time that the plow is reversed. is accomplished automatically rather than by the manual operation of a pull rope, as is required in the patented plow.

A in the patented plow, the forward end of the draft bar I4 is pivotally connectedto the tractor hitch plate I8. Likewise, as in the patented plow, the plow 3 is provided with an armate cross member I85 to the forward side of which is secured laterally spaced latch keepers Ifitand I5 5. The rear end of the draft bar i4 is provided with a bifurcated portion S96 which engages over and under the arcuate cross bar I65 which guides the rear end of the draft bar in its transverse swinging movement. In lieu of the single latch as providedin the patented structure on the draft bar I4, the plow 9 is provided with a pair of latches I61 and I98 which are pivotally mounted at their lower ends on a pivot pin asewhich is connected to the lower part of the bifurcated portion I95 for swinging movement of the latch members I51 and I 98 forwardly and rearwardly of the plow frame from positions in front of the cross member I05. The upper, free end of each latch member I97 and I93 is connected by acontractile spring 200 to the rear end of the upper part of the bifurcated portion I96 so that the latches I91 and I98 are urged rearwardly by the prings 200 toward the cross bar led and toward positions for latching engagement with the latch keepers I53 and E64, respectively. A pair of guide sleeves I are supported in forwardly converging relationship to one another on the upper end of the pivot I5 by a supporting member 202. The forward end portion of a pair of push rods 203 and 204 are reciprocally mounted in the sleeves 20 I said push rods extending rearwardly therefrom in diverging relationship to one another and being pivotally connected at their rear end by horizontally disposed pivots 204a to the two latch elements I30. Accordingly, when either latch element 530 is swung forwardly by its bottom extension I33 engaging a cam ring I32, the push rod 253 or 204 connected thereto will be displaced forwardly through its guide sleeve 20I and relatively to the other push rod. The push rod 203 is connected by a flexible member 205 to the upper end of the latch lever is! and the push rod 204 is similarly connected by a econd flexible member 205 to the other latch lever l'98, said flexible members being secured to apertured ears 20E'which depend from the push rods and which are disposed forwardly of the latch levers.

In lieu of the chains I50 and I56 of the patented plow structure, an intermediate link of a chain is secured to one end of a contractile coil spring 201 which is' disposed below the draft bar it. The end 208 and 200 of said chain extend forwardly from the spring 201 in diverging relationship to one another and are anchored at their forward ends at 2I0 to laterally spaced portions of the rear end of the draft vehicle I'I. Obviously, separate chains may be utilized between each point 2I0 and the spring 20'! if desired. A strap member 2II is attached at its upper, rear end by a fastening 2 I2 to the under side of the draft bar I4, rearwardly of its pivot I5. The strap member 2 I I has a downwardly and forwardly offset opposite free end to which one end of a chain 2I3 is adjustably connected. The chain 2I3 extends fowardly from the strap 2 and is connected at its opposite end to the rear end of the spring 201. Accordingly, the chain 253 may be adjusted for varying the tension on the spring 201.

Assuming that the latch I98 is engaging the keeper I04, as illustrated in Figures 2 and 3, the draft bar I4 will have its rear end offset to the left so that the axis of the plow will be'offset to the left of the axis of the draft vehicle looking from rear to front thereof. The latch I98 isallowed to assume alatching position as the push rod 204 is in a rearmost position whereas the latch I0? is held in a forward, inoperative position as the push rod 203, to which it is connected is dis: placed forwardly since the cam ring I32 is engaging the extension I33 of the latch hook I30 to which the push rod 203 is connected. As the plow 9 reaches an end of the field and the beam structure 30 thereof is tumbled the draft vehicle I I executes a figure 8 turn and in the last part of which turn the tractor is turning to the right as seen in Figure2. The tumbling of the plow structure 30. is com leted during the last'part of the figure 8 turn and consequently the push rod 203 has been released to move backwardly to release the latch I91 and as the plow structure 30 completes its swinging movement the cam ring l32 connected to the part 35. engages the other mem ber I33 of the left-hand latch I30 to swing the upper portion of said latch forwardly and therebydisnlace the push rod 204 forwardly. At the time that this occurs the chain 208 will be taut and the chain 209 relatively slack and the spring 20'! will be under tension. Accordin ly. when the push rod 204 is thus. displaced forwardly a forward pull is exert d on the latch I08 thereby through its cable 205 to disengage said latch from the keeper IE4. When this occurs the draft bar I l will be swung counterclockwise as seen in Figure 2 on its pivot I5 sufliciently so that the latch I91 will pass the c m surface of the keeper Hi3 and will engagebehind said keeper to latchthe draft bar I4 so that the plow will then be offset to the other side or to the right of the axis of the dra t vehicle I1. It will thus be seen that the offsetting of the axis ofthe plow 9 relatively to the draft vehicle is accomplished automatically when the plow is turned with the draft vehicle at each end of the field whereas in the patented plow the latch must be manually released. In accomplishing the offsetting of the draft bar I 4, with the patented plow the rope I66 is pulled to disengage the latch I60 after which the last half of the figure 8 turn must be made short and quick in order to offset the draft bar sufiiciently to engage the latch with the other keeper or plate. With the improved offsetting; means of the plow 9 not only is the offsetting accomplished automatically but additionally the last half of the figure 8 turn is not required to be made sharp and fast since the tension of the spring 20! will cooperate with either chain end 208 or 209 which is tensioned-to'provide adequate power to swing the draft bar In sum;

ciently when unlatched from one of the keepers to a position to be latched by the other keeper.

It will thus be seen that a tumble plow of improved construction has been provided wherein manual operation is reduced to a minimum and by relatively simple structural changes the operation of the plow has been rendered substantially automatic in all respects. Further, the plow 9 in addition to having been rendered more nearly fully automatic has also been improved structurally so that it is substantially foolproof and may not be inadvertently released from a proper operating position or inadvertently prevented from assuming a proper operating position including the offsetting of the plow relatively to the axis of the draft vehicle.

Various modifications and changes are contemplated and may obviously be resorted to, without departing from the spirit or scope of the invention as hereinafter defined by the appended claims.

We claim as our invention:

1. A two-way plow comprising a frame having a front end and a rear end, a reversible beam structure rotatably mounted about a horizontal axis on the rear end of the frame, left and right hand plow elements carried by the beam structure and disposed alternately in working positions, a draft bar pivotally mounted on a vertical axis intermediate of its ends on the forward end of the frame, said draft bar being adapted to be connected at its forward end to a draft vehicle, means adjustably latching the other rear end of the draft bar to the frame on either side of the longitudinal axis of the plow in positions for offsetting the axis of the plow to either side of the longitudinal axis of the draft vehicle, said adjustable latching means including a releasable latch structure carried by the draft bar, a latch releasing unit connected to the latch structure and actuated by tumbling of the beam structure to unlatch the draft bar from the frame, and means connecting the draft bar and draft vehicle for swinging the rear end of the draft bar, when unlatched, laterally of the plow and across the longitudinal axis thereof into a position to be automatically latched in an opposite offset position when the draft vehicle and plow are turned to reverse their direction of travel.

2. A plow structure as in claim 1, said latch structure including a pair of latch elements normally disposed in operative positions, said latch releasing unit including individually actuated elements each connected to one of said latch ele ments and alternately operated by tumbling of the beam structure for alternately moving and retaining the latch elements in retracted, inoperative positions.

3. A plow structure as in claim 1, said means connecting the draft bar and draft vehicle including flexible elements connected to laterally spaced portions of the draft vehicle and extending rearwardly in convering relationship to one another, and a contractile spring forming a connection between the converging ends of said flexible elements and the rear end of said draft bar.

4. A two-way plow comprising a frame, a reversible beam structure rotatably connected to the frame for turning movement in a vertical plane longitudinally of the frame, right and left hand plow elements carried by the beam structure and alternately disposed in working positions, laterally spaced ground wheels supporting the frame and vertically adjustable relatively thereto, each of said ground wheels having an upright axle portion slidably connected to the frame, linkage means pivotally connected to the upper end of each axle portion and to said frame for adjusting the elevation of the wheels individually relatively to the frame, pivotally mounted latch members releasably engaging said linkage means for supporting the frame in an elevated position relatively to the wheels, manually actuated means for releasing the latch elements from said linkage means, and springs connecting the latch elements to the vertical axle portions for retaining said latch elements in released positions when the frame is displaced downwardly from a fully elevated position relatively to the wheels. 7

5. A plow structure as in claim 4, and link and lever means forming a connection between said latch elements whereby the tensioning of the spring of either latch element will retain both latch elements in inoperative positions.

6. A plow structure as in claim 4, and link and lever means forming a connection between said latch elements whereby the tensioning of the spring of either latch element will retain both latch elements in inoperative positions, manually actuated means simultaneously moving said latch elements to released positions, a beam engaging latch, means connecting said beam engaging latch to the manually actuated means for releasing said beam engaging latch by operation of said manually actuated means, said last mentioned means including a link connected to said manually actuated means and normally inoperatively disposed with respect thereto whereby the beam engag'mg latch is unaffected by operation of the manually actuated means, a linkage unit connected to said link and lever means and operated when the link and lever means is operated by either of said springs for operatively connecting the link to the manually actuated means whereby operation of the manually actuated means will disengage the beam engaging latch to permit tumbling of the beam structure.

'7. A plow structure as in claim 4, and link and lever means forming a connection between said latch elements whereby the tensioning of the spring of either latch element will retain both latch elements in inoperative positions, a beam latch releasing means including a link inoperatively connected to said manually actuated means, and a member carried by said manually actuated means and operatively connected to the link and lever means for operatively connecting said manually actuated means to the beam latch releasing link when said link and lever means is actuated by the tensioning of either of said springs.

ROBERT A. WALKER. EARL V. WALKER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,188,413 Markel Jan. 30, 1940 2,327,927 Orelind Aug. 24, 1943 FOREIGN PATENTS Number Country Date 675,469 France Nov. 7, 1929 

